烟草幼苗对复合盐碱的生理响应

  目的  研究烟草幼苗在复合盐碱处理下的生理代谢变化。  方法  以n（NaCl）:n（Na₂SO₄）:n（NaHCO₃）=1:1:1的比例，设置5个质量浓度复合盐碱处理，测定各处理烟苗根系指标和叶片生理指标。  结果  1）随着复合盐碱浓度增加，烟苗总根长呈降低趋势，根表面积、根尖数和根活力都表现出先升后降趋势；2）低浓度短时间盐碱处理促进叶绿素积累，时间延长或浓度增加使叶绿素含量下降；3）随处理浓度升高和时间延长，叶片含水率下降，MDA含量和相对电导率升高，可溶性糖和脯氨酸含量先升后降；4）低浓度盐碱处理ABA含量变化不明显，ZR含量下降，高浓度盐碱处理时这两种激素含量均有升高趋势。  结论  0.3%复合盐碱、短期的复合盐碱处理可促进烟苗的生长，盐碱胁迫时间延长或浓度升高则会影响烟株正常生长发育。 

Physiological responses of tobacco seedlings to saline-alkali stress

Objective]This study aims to investigate the physiological and metabolic changes of tobacco seedlings under compound saline-alkali treatment.Method]Five mass-concentrations compound saline-alkali treatments were set up,with the ratio of n(NaCl):n(Na2SO4):n(NaHCO3)=1:1:1.The root index and leaf physiological index under each treatment were measured.Results]1)As the compound saline-alkali concentration increased,the total root length of tobacco seedlings decreased,and the root surface area,root tip number,and root vigor all showed a tendency of first increasing and then decreasing;2)low-concentration and short-term saline-alkali treatment could promote chlorophyll accumulation,but prolonged treatment time or increased concentration of saline-alkali treatment would decrease chlorophyll content of tobacco seedlings;3)With the increase of treatment concentration and extension of treatment time,leaf moisture content decreased,MDA content and relative conductivity increased,soluble sugar and proline content increased first and then decreased;4)The ABA content of tobacco seedlings treated with low-concentration saline-alkali treatments did not change significantly,but the ZR content decreased.The contents of two hormones both increased during high-concentration saline-alkali treatments.Conclusion]Under the conditions of this experiment,0.3%compound saline-alkali treatment and short-term compound saline-alkali treatment can promote the growth of tobacco seedlings.Prolonged saline-alkali stress time or increased treatment concentration will affect the normal growth and development of tobacco plants.